20505 research outputs found
Sort by
Comparative evaluation of ion-exchange resins for natural organic matter removal from power plant source waters
No full textNatural organic matter (NOM) in source waters presents significant operational challenges for thermal power generation, including membrane fouling, scaling, and the formation of disinfection byproducts (DBPs). This study evaluated the performance of three macroporous strong-base anion exchange (IEX) resins, polyacrylic (A860S), polystyrenic (A502PS), and a polystyrene-polyacrylic blend (MPR1000), for dissolved organic carbon (DOC) removal from two industrial water sources: Vaal River raw water (Vaal RW) and Medupi ultrafiltrate (Medupi UF). Batch experiments and kinetic modelling revealed that the pseudo-second-order model best described the adsorption behaviour, indicating chemisorption as the dominant removal mechanism. Despite having the lowest ion-exchange capacity, MPR1000 achieved the highest DOC uptake in Medupi UF (47.4 ± 3.2%), while A860S demonstrated the most consistent performance across both matrices (up to 77.3 ± 4.2% in Vaal RW). In contrast, A502PS exhibited limited effectiveness due to diffusional constraints. Intraparticle diffusion analysis confirmed multi-stage mass transfer, and liquid chromatography-organic carbon detection showed preferential removal of humic substances and building blocks, with minimal uptake of low molecular weight acids and neutrals. Variations in removal efficiency were attributed not to the molecular weight of NOM but to differences in aromaticity (SUVA254) and anionic composition, particularly the sulphate content. These findings underscore the importance of aligning resin matrix characteristics with specific water chemistries to optimise IEX performance for industrial water treatment, particularly under sulphate-rich conditions common in power plant operations.Journal of Water Process Engineerin
A review of an ontology-based digital twin to enable condition-based maintenance for aircraft operations
No full textThe concept of digital twins has been studied for over two decades and the core tenet lies in it being a “digital representation of a connected physical object”. Utilization of digital twins promises to enable superior decision-making, enhanced operational understanding and future predictions to enable levels of Condition Based Maintenance (CBM) through Integrated Vehicle Health Management (IVHM) which exceeds existing capabilities. Digital twins are being embraced by many industries, including aviation, and are often depicted as electronic images of an asset of interest. However, in a less visually appealing manner, they can also be described simply as a collection of data in an organized and easily accessible format from across the lifecycle which describes a feature that addresses a specific use case. This review demonstrates how the creation and maintenance of digital twins will play a critical role in enhancing IVHM to enable CBM within the aerospace industry. Through a literature review, this paper demonstrates the need for digital twins, of a sufficient level of fidelity, to facilitate the transition to being condition based through deeper levels of operational and component understanding. It emphasizes how detailed knowledge, represented through ontologies, regarding component design, manufacturing, and operational history aid in achieving the desired fidelity levels. By synthesizing insights from various industries with a focus on aerospace applications, this paper aims to provide a comprehensive understanding, focused on the aviation industry, of digital twin definitions, their creation processes, fidelity measurement, and their implications for CBM, while acknowledging the limitations of the current research landscape.Applied Science
3D-printed models in the courtroom: mock-jurors’ perceptions and experiences of 3D-printed models of human skeletal remains
No full textThe use of 3D-printed models of skeletal remains has notably enhanced jurors’ comprehension of forensic evidence and skeletal trauma, enabling clearer interpretations and diminishing the confusion associated with expert terminology. However, the hands-on tactile sensory engagement with these highly realistic 3D-printed models of human remains could be more distressing than traditional passive modalities. In the first study, to qualitatively examine jurors’ perceptions of 3D-printed skeletal remains as evidence, mock-juror participants read a written summary of a murder trial before interacting with an accurate 3D-printed model of a real murder victim’s skull showing evidence of gunshot trauma. The deliberations were audio-recorded and subjected to reflective inductive semantic thematic analysis, which identified four critical themes: ‘Realistic and creepy’, ‘Overcoming uncomfortableness’, ‘Illustrative tool’ and ‘A piece of the puzzle’. The findings revealed that 3D-printed models have an emotional impact on jurors and indicate that caution should be exercised in their use in courts.Psychiatry, Psychology and La
A baseline assessment of residential wood burning and urban air quality in climate-vulnerable chilean cities
No full textThe data used in this study was downloaded in ASCII format from the SINCA network belonging to the Chilean Ministry of the Environment http://sinca.mma.gob.cl/This study presents a comprehensive latitudinal analysis of air particulate matter (PM) across an 1400 km pollution corridor spanning Chile’s central-southern zone. We systematically analyzed PM2.5 and PM10 concentrations across eight major urban centers (2014–2015), providing crucial pre-Paris Agreement baseline data for South America’s most extensive air quality monitoring network. Our analysis reveals significant pollution gradients, with Coyhaique ranking one of the world’s most severely polluted cities (95th percentile globally, WHO database) and demonstrating an extreme 86% fine particulate matter ratio that far exceeds international urban standards. Residential wood combustion (RWC) demonstrates systematic correlations with fine PM concentrations (R2 > 0.96), suggesting RWC is the dominant pollution driver across multiple climate zones. The documented pollution patterns represent a concerning continental-scale environmental pattern, with 4900–6500 annual premature deaths directly attributable to PM2.5 exposure-one of the highest per-capita pollution mortality rates in South America. This work provides a methodological framework applicable to mountain-valley pollution systems globally while addressing critical knowledge gaps in regional air quality science. The evidence indicates the need for urgent implementation of comprehensive wood combustion control strategies and positions this research as essential baseline documentation for both national air quality policy and international climate change assessment frameworks.Urban Scienc
Dual-gradient wettability-patterned surface for droplet rectification and targeted transport
No full textDroplet self-transport holds significant implications for applications such as water harvesting, microreactors, and microfluidic chips. Achieving precise and efficient droplet self-transport is therefore crucial. Herein, a dual-gradient wettability-patterned surface (DWPS) incorporating both wettability and structural gradients is proposed, where the wettability gradient facilitates ultrafast droplet transport, while the structural gradient serves to rectify the transport direction, collectively achieving directional droplet rectification and ultrafast targeted self-transport. The influence mechanism of energy conversion on droplet self-transport behavior during oscillatory motion is elucidated. The oscillatory behavior during droplet self-transport can be effectively suppressed through a droplet coalescence strategy. Compared to the single wettability or structural gradient surfaces, the structural gradient surface exhibits the lowest transport efficiency. Although the droplet self-transport efficiency on the DWPS is also lower than that on the wettability gradient surface, it enables precise droplet transport. The mechanisms underlying the self-transport behavior and efficiency variations on the three model surfaces are revealed through an analysis of the relationship between solid-liquid interfacial energy and droplet potential energy. These findings provide a theoretical foundation for the design of functional surfaces aimed at achieving precise droplet self-transport.This work was supported by the National Natural Science Foundation of China (12272151, 52475301), Major Program of National Natural Science Foundation of China (NSFC) for Basic Theory and Key Technology of Tri-Co Robots (92248301), The Natural Science Foundation of the Jiangsu Higher Education Institutions of China (24KJB460010)Langmui
Comparative sampling methodologies for detecting and quantifying 2,4,6 trinitrotoluene post-blast traces in water
Get PDFThis study addresses the analytical challenges associated with recovering explosive residues, focusing on the identification of 2,4,6-trinitrotoluene (TNT) in water samples. It evaluates the practicality, efficiency, and representativeness of three sampling methodologies: traditional grab sampling (GS), composite sampling (CS), and 3-D multi-increment sampling (3D-MIS). High-Performance Liquid Chromatography (HPLC) was employed for explosive identification. Post-blast sampling of TNT residues from high-order and low-order deflagrations was conducted to assess each method's efficacy and limitations in detecting trace and bulk contaminations. The experiments were conducted at the Alford Technologies Group range in Broadmead, UK, with analysis performed at the Defence Academy in Shrivenham, UK. Key findings highlight the varying effectiveness of each sampling method, with implications for enhancing detection sensitivity and accuracy in post-blast scenarios. This study underscores the importance of selecting appropriate sampling strategies tailored to different contamination scenarios, thereby informing more effective response protocols in CBRNe incidents involving water environments.AVT-394-RSM on Water sampling, monitoring and control/remediation for live-fire military range
Design space exploration of gas turbine based ship propulsion systems
Get PDFThe conceptual design of a ship propulsion system, developed during the early
stages of the overall ship design process, has a very large impact on the overall
design and performance of a ship. Gas turbines are often utilized for warship
propulsion systems designed to fulfil requirements of high ship speed and power
density. To achieve a high overall system-level efficiency, gas turbines are often
used in combined architectures with diesel engines along with geared, electric or
hybrid transmission systems driving multiple propulsors. The process for the
development of the conceptual design for such ‘combined’ systems, designed to
achieve multiple and often conflicting design objectives, is significantly more
complex compared to that for systems where a single-engine drives a propulsor.
A number of approaches are currently used in practice towards the conceptual
design of a ship, ranging from manual ‘design lanes’ based iterative approaches,
to computerized overall ‘ship as a system’ design synthesis approaches.
Towards the conceptual design of the propulsion system, both these approaches
pose their own limitations, wherein the approach of the manual iterative design
process relies heavily on the preferences of experts and approximations based
on past experience; while the ship design synthesis approach usually yields good
results generally if the candidate propulsion architectures are based on existing
designs.
This research work proposes a model-based process for the design space
exploration using a model-based ‘Techno-economic & Environmental Risk
Assessment’ (TERA) approach. To undertake feasibility and performance
analysis of the candidate propulsion system architectures, the process involves
building performance models of the candidate propulsion system architectures at
this very early stage the overall design process of the ship and utilizing the
generated results as the basis of design related decisions.
For undertaking the performance modelling of the multiple candidate propulsion
system architectures, an agile modelling and simulation framework was
considered essential that could handle the complexity of ‘combined’ propulsion
plants. To achieve this, a component-based modelling software, ‘Poseidon +’,
has been developed as a part of the present work which enables 0-D modelling
of gas turbine engines as well as the entire propulsion system in the same
framework. A key aspect of this work was the development of an algorithm that
analyses the direction of the torque transmission across the complex
transmission system of ‘combined’ plants, based solely on the based on the
states of the engine and clutches.
For undertaking TERA, a suite of ‘Multiple-Criteria Decision-Making’ (MCDM)
methods were selected and applied to select a compromise solution from
competing propulsion system architectures, using a combination of performance
data generated from simulation of developed models, and comparative expert
opinions-based metrics for information not available early in the ship design
process. To execute the MCDM procedure, a methodology of deriving weights of
the competing design criteria using a combination of hierarchal and network
structure, considering the degree of relationships between the design criteria, has
been demonstrated.
The overall proposed approach for design space exploration of gas turbine based
‘combined’ ship propulsion systems has been demonstrated towards the
conceptual design analysis of two notional ship designs. The results of the
analysis show the effectiveness of the proposed procedure for design space
exploration of ship propulsion systems.PhD in Aerospac
An innovative digital liquid metal manufacturing method for aerospace applications: incorporating life cycle assessment for sustainability
Get PDFThe Ultra Clean Cast (UCC) system presents an innovative approach to aerospace manufacturing by prioritizing component quality and manufacturing repeatability. It incorporates a cradle-to-gate life cycle assessment to highlight its additional environmental benefits, with a greater focus on enhancing sustainability. This novel approach improves upon traditional shape-casting by maintaining the high cleanliness of melt metal, critical for aluminum alloys, and difficult to achieve in general for aerospace parts, under varied conditions. By providing a sustainable, cost-efficient route for fabricating complex components, UCC is adaptable across aerospace platforms and evaluates the use of recycled aluminum, supporting the sector’s shift towards a circular economy. This paper outlines the UCC system’s integration of technological advancements with environmental responsibility, incorporating recycled aluminium raw material, material manufacturing, and product manufacturing stages. This system provides a new benchmark for environmentally friendly aircraft manufacturing by outlining process improvements and their implications for industry sustainability and efficiency. The findings highlight UCCs potential to affect aerospace manufacturing in the future, combining high-quality output with environmental considerations.The authors gratefully acknowledge the funding by the Ultra Clean Cast DLMM Program No 10065261.20th Global Conference on Sustainable Manufacturing (GCSM 2024)Lecture Notes in Mechanical Engineerin
Towards a CubeSat relevant mission payload for demonstrating aspects of In-Situ ResourceUutilisation (ISRU) on a C-type Near-Earth Asteroid (NEA)
Get PDFNearly 50 years ago, humankind long dreamed of colonizing or exploiting the
neighbouring planets Mars, the Moon, comets, and asteroids in our Solar System
for technological and profit-oriented purposes. The concept of In-Situ Resource
Utilisation (ISRU) is likely to be a means to achieving those dreams. High cost
and the possibilities of failure associated with the development of full-size ISRU
spacecraft, early use of CubeSat payloads for ISRU technology demonstration
would serve as a technology readiness level (TRL) driver and a de-risking
technology. Mars Oxygen In-Situ Resource Utilization Experiment (MOXIE) is the
only small size ISRU demonstration payload currently flown and on Mars to
demonstrate oxygen extraction from the Martian atmosphere. The regolith/soils
present in smaller bodies are identified to be rich in minerals resources such as
precious metals, volatiles, organic and non-organic materials that can be
harnessed for the good of humankind. This PhD research work aimed to advance
an initial CubeSat-like payload design to demonstrate an ISRU process on a C –
type near-earth asteroid (NEA).
The result of the literature review performed was, the project background was
elaborated. From the trade-off studies carried out for the selection process of the
potential destinations and the ISRU process, C-type NEA 162173 Ryugu JU3,
and hydrometallurgical sulphuric acid leaching experiment on olivine minerals
have emerged as the winners. System requirements are generated, and for the
proposed CubeSat payload system architecture comprising of sample acquisition
subsystem, reaction chamber subsystems, acid solution delivery and extraction
subsystem, the electroplating/wining subsystem, and analytical subsystem, an
initial overall payload system design was achieved. This project has been focused
on the re-design and manufacturing of the reaction chamber subsystems and top-
plate system, and the design and manufacture of the leaching and the liquid
handling sub-system (LHS). The result of laboratory hydrometallurgical sulphuric
acid leaching experiments carried out found the optimal condition to achieve
higher metal extraction from the reaction mixture occurs at 5M H₂SO₄ acid
concentration, 1:5 mineral to acid volume ratio (1g/5ml), and in a state of
agitation. The inclusion of bromophenol blue (BPB) dye in the leaching
experiment to eliminate the initial use of litmus paper, detect the loss of acid
concentration by providing a real-time visual colour transition from yellow to blue,
within the required acid pH range and would expect to be compatible with future
flight implementation. Using the 5M H₂SO₄ acid concentration, the BPB dye
solution was observed to degrade and change to colourless. Sourcing an
alternative dye that is stable in 5M H₂SO₄ acid to mitigate against this looming
challenge was suggested for future work. The payload system design together
with the optimal leaching condition generated, informed the Breadboard (BB)
payload prototype system design, component selection, and manufacture. A
version of the Reaction Chamber Subsystem (RCS) oven implemented in a co-
running CubeSat relevant payload design (ISRU water extraction), and based on
the initial size and volume, appears to be suitable for this project. The RCS is
manufactured from a material that is sulphuric acid-resistant and was re-designed
to allow for interfacing to the LHS. The top plate implemented on CubeSat based
ISRU water extraction project was adapted, re-designed, and manufactured from
a material that is sulphuric acid-resistant to enable the accommodation of the
LHS and the associated system that will ensure efficient interaction between acid
solution and the collected olivine regolith. The LHS subsystem is comprised of
valves, pumps, manifolds, reservoirs, tubing connectors, and fittings. These
components are interconnected, and they interact to establish the LHS that will
allow for efficient liquid handling in microgravity. The LHS is operated to deliver
H₂SO₄acid solution from the reservoir into the RCS and the extraction of the
leachate from the RCS respectively.
In the conclusion, the manufactured BB payload system was operated to simulate
hydrometallurgical leaching and aspects of liquid handling processes. The result
indicates the usefulness of the process and its feasibility for CubeSat
implementation. Additional tests need to be performed to further validate the BB
payload system’s usefulness. Also, various future works are presented that will
increase the technology readiness level of the design concept to further validate
the usefulness of the ISRU BB payload system.PhD in Aerospac
Embodying routine replication dynamics: an ethnographic study on the impact of the body in routine replication in the Royal Air Force
Get PDFWe examine the role of embodiment in routine replication by investigating how the Royal Air Force adapted the loaded march (tabbing) routine from its Ground Combat Training program into Initial Officer Training. Routine replication required adjustments due to bodily differences among trainees, balancing flexibility with recognizability. Using enactive ethnography—where the first author physically participated in the marches—our 30-month ethnographic study reveals that routine replication is shaped by three bodily adaptation mechanisms: ‘playing with rhythm,’ ‘coping with injuries,’ and ‘dealing with emotions’. These mechanisms illustrate how bodies actively shape routine enactment, challenging conventional views of routine replication as a purely cognitive or procedural process. Our study advances Routine Dynamics by integrating an embodied perspective into the replication dilemma and demonstrating how bodily constraints and adaptations influence routine evolution. Additionally, we contribute methodologically by showcasing enactive ethnography as a powerful approach for studying embodiment in organizations.16th International Symposium on Process Organization Studies (PROS